Load limiter for self-energizing drive

ABSTRACT

A load limiter for a self-energizing drive mechanism which has a rotating disk, a wheel driven therefrom and a swing mechanism on which the wheel is swung toward and away from the disk, said limiter comprising stop means for limiting swinging motion of the swing mechanism toward the disk and yieldable spring biased mounting means for the disk on which the disk will yield prior to engagement of the stop means, whereby the pressure between the wheel and disk is limited to the spring bias of the disk mounting means.

United States Patent [191 Enters et a1.

mlMarch 13, 1973 LOAD LIMITER FOR SELF- ENERGIZING DRIVE [75] Inventors:Edward W. Enters, Fredonia; Warren H. Price, Sheboygan, both of Wis.

[73] Assignee: Gilson Bros. Co., Plymouth, Wis.

[22] Filed: Oct. 22, 1971 [21] Appl. No.: 191,646

[52] US. Cl ..74/l96, 74/202 [51] Int. Cl. ..F16h 15/08, Fl6h 13/02 [58]Field of Search ..74/l96, 199, 194, 202

[ 56] References Cited UNITED STATES PATENTS 3,445,991 5/1969 Hanson etal ..74/l94 X Mollen ..74/l94 X Prien, Jr. ..74/194 X PrimaryExaminer-Leonard H. Gerin Attorney-Wheeler, House & Wheeler 57 ABSTRACTA load limiter for a self-energizing drive mechanism which has arotating disk, a wheel driven therefrom and a swing mechanism on whichthe wheel is swung toward and away from the disk, said limitercomprising stop means for limiting swinging motion of the swingmechanism toward the disk and yieldable spring biased mounting means forthe disk on which the disk will yield prior to engagement of the stopmeans, whereby the pressure between the wheel and disk is limited to thespring bias of the disk mounting means.

4 Claims, 3 Drawing Figures LOAD LIMITER FOR SELF-ENERGIZING DRIVEBACKGROUND OF THE INVENTION Copending United States application Ser. No.

101,471 filed Dec. 28, 1970, now abandoned, illus- SUMMARY OF THEINVENTION The object of the present invention is to limit theself-energizing reaction loads between the rotating disk and drivenwheel in such a drive mechanism. For this purpose the invention providessuitable means for limiting'the extent of the swinging motion of thewheel toward the disk and provides for a yieldable, spring biased diskmounting on which the disk will yield prior to engagement of the stopmeans, whereby the pressure between the wheel and disk is limited tothat imposed by the spring bias of the disk mount. The drive isselfenergizing to the extent of compressing the spring until the stopengages, but no more.

Other objects, features and advantages of the invention will appear fromthe following disclosure.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a reduced scale perspective viewof a snow thrower which is one example of a mechanism in which the driveof the present invention can be incorporated.

FIG. 2 is an axial cross section through a portion of the snow throwerwhich incorporates a drive mechanism embodying the present invention.

FIG. 3 is a transverse cross section through the apparatus shown in FIG.2.

DESCRIPTION OF THE PREFERRED EMBODIMENT I Although the disclosure hereofis detailed and exact to enable those skilled in the art to practice theinvention, the physical embodiments herein disclosed merely exemplifythe invention which may be embodied in other specific structure. Thescope of the invention is defined in the claims appended hereto.

The snow thrower illustrated in FIG. 1 is for exemplification only, asthe drive mechanism of the present invention can be incorporated inother apparatus. The snow thrower has an auger housing containing anauger 11 which gathers snow to the center of the auger from which it ismoved rearwardly into a second stage impeller housing 12 and is thencethrown through the discharge chute 13. The snow thrower is supported andconveyed on power operated traction wheels 14. Drive and transmissionmechanism within the housing 15 drives the traction wheels 14.

As' best shown in FIG. 2, and as also shown in copending United Statesapplication Ser. No. 101,471 aforesaid, one form of the drive andtransmission mechanism comprises tandem axially spaced friction disks16, 17 and an intermediate shiftable wheel 18. Disks 16, 17 are coaxialon shaft 28 and intermediate wheel 18 is mounted on swing mechanism suchas a swingable gear housing 19 which pivots around the shaft 22. Wheel18 rotates around the axis of shaft 23 in gear housing 19. The gears inhousing 19 transmit the motion of the wheel 18 to the shaft 22 uponwhich the traction wheels 14 are mounted, as shown in FIG. 3.

Power from the snow thrower engine 24 is delivered to shaft 28 throughbelt 25 and pulley 26 which is formed on the periphery of disk 16. Disk16 has a hub 27 to which shaft 28 is coupled, as by splines 29.

In accordance with the present invention, the shaft 28 carries anaxially shiftable sleeve 31 which is telescopically related to the shaft28. Sleeve 31 functions as a support means for the disk 17 which iswelded thereto at 38. Shaft 28 also carries an axially fixed sleeve 32,affixed to the shaft 28 by a pin 33. The two sleeves 31, 32 haveoverlapping, interfitting spline forming end shoulders 34, 35.Accordingly, sleeve 31 is free to move axially on the shaft 28 but stillbe keyed for rotation therewith, because of the splined shoulders 34,35.

Shaft 28 also carries a spring container cup 36 which functions as anend abutment for the coil spring 37 which has one end seated in the cup36, and the other end against the base of the disk 17. Spring 37 isgiven a pre-determined resilient bias in an amount sufficient to biasthe disk 17 to the left in FIG. 2 (to its broken line position) untilthe shoulders 34, 35 of the sleeves 31, 32 abut endwise.

Housing 15 is provided on its inside surface with a stop abutment 41which is in the path. of movement of the turned end 43 of stop arm 42.Arm 42 is welded or otherwise attached to the swing bracket 40 which ispivotally mounted on shaft 22 and which supports the end of the shaft 23on the opposite side of wheel 18 from gear box 19.

Gear housing 19, bracket 40 and wheel 18 are caused to swing about theaxis of traction wheel shaft 22 by any suitable control mechanism. As anexample, a control handle 44 is mounted on the control column 45 of thesnow thrower. Handle 44 projects from a lever 46 which is pivoted on pin47 to a bracket 48 mounted on the column 45. A control link 51interconnects the lever 46 with a bracket arm 52 welded to the gearhousing 19.

Typically there will be three positions for the control handle 44,namely, reverse, neutral and forward, in dicated by legends R, N, and Fin FIGS. 1 and 2. In the reverse position the wheel 18 will be swung toengage its rubber tire 49 with the disk 16, as indicated at 49R in FIG.2. In neutral position the tire 49 of wheel 18 will be free ofengagement with both of the disks 16, 17, as indicated at 49N in FIG. 2.In forward position tire 49 of wheel 18 will engage the disk 17, asindicated at 49F in FIG. 2.

When the wheel 18 is in reverse and neutral positions, as indicated at49R and 49N in FIG. 2, it will be out of contact with the disk 17, thusallowing the spring 37 to move the disk 17 and its sleeve 31 axiallyalong the shaft 28 to the broken line position therein illustrated.However, as the gear box 19 is swung toward disk 17, tire 49 of wheel 18will engage the disk 17 and begin to slide the disk 17 and its sleeve 31axially along the axle 28 and in the direction of arrow 53. Spring 37will yield and undergo further compression during this movement, untilarm 42 reaches its full line position in FIG. 2, at which point itslateral projection 43 engages the stop abutment 41 as is also shown inFIG. 3. At this point the spring 37 has been compressed to apre-determined amount and the pressure between the wheel 18 and disk 17will increase no further, but will be maintained at the pre-determinedsetting. This setting is such that the friction load caused by thereaction of the wheel 18 against the disk 17 will not exceed apredetermined tolerable amount, but there will nevertheless be amplefriction between the wheel 18 and the disk 17 to transmit all the powerthat is necessary to drive the traction wheels 14.

In this manner the drive will retain its self-energizingcharacteristics, but excessive load or drag is precluded.

We claim:

1. In a drive mechanism having a rotating disk, a wheel driventherefrom, and a swing mechanism on which said wheel is swung toward andaway from said disk, the improvement for limiting the load generated bythe drive mechanism as a consequence of the reaction between the diskand wheel and comprising stop means for limiting swinging motion of theswing mechanism toward said disk and yieldable resiliently biasedmounting means for the disk on which the disk will yield prior toengagement of the stop means, whereby the pressure between the wheel anddisk is limited to the bias of the said mounting means.

2. The invention of claim 1 in which the stop means comprises a fixedabutment and a stop arm on the swing mechanism.

3. The invention of claim 1 in which the mounting means comprisessupport means on which the disk is axially shiftable and a springbiasing said disk against such axial shift.

4. The invention of claim 3 in which said mounting means comprises ashaft, said support means comprising a sleeve telescoped over said shaftand a spline coupling between said shaft and sleeve.

1. In a drive mechanism having a rotating disk, a wheel driventherefrom, and a swing mechanism on which said wheel is swung toward andaway from said disk, the improvement for limiting the load generated bythe drive mechanism as a consequence of the reaction between the diskand wheel and comprising stop means for limiting swinging motion of theswing mechanism toward said disk and yieldable resiliently biasedmounting means for the disk on which the disk will yield prior toengagement of the stop means, whereby the pressure between the wheel anddisk is limited to the bias of the said mounting means.
 1. In a drivemechanism having a rotating disk, a wheel driven therefrom, and a swingmechanism on which said wheel is swung toward and away from said disk,the improvement for limiting the load generated by the drive mechanismas a consequence of the reaction between the disk and wheel andcomprising stop means for limiting swinging motion of the swingmechanism toward said disk and yieldable resiliently biased mountingmeans for the disk on which the disk will yield prior to engagement ofthe stop means, whereby the pressure between the wheel and disk islimited to the bias of the said mounting means.
 2. The invention ofclaim 1 in which the stop means comprises a fixed abutment and a stoparm on the swing mechanism.
 3. The invention of claim 1 in which themounting means comprises support means on which the disk is axiallyshiftable and a spring biasing said disk against such axial shift.